code: def setUp(self):
      self.pred = []
      data_sample = TextRecogDataSample()
      pred_text = LabelData()
      pred_text.item = "helL"
      data_sample.pred_text = pred_text
      gt_text = LabelData()
      gt_text.item = "hello"
      data_sample.gt_text = gt_text
      self.pred.append(data_sample)
      data_sample = TextRecogDataSample()
      pred_text = LabelData()
      pred_text.item = "HEL"
      data_sample.pred_text = pred_text
      gt_text = LabelData()
      gt_text.item = "HELLO"
      data_sample.gt_text = gt_text
      self.pred.append(data_sample)
  
file_path: mmocr/tests/test_evaluation/test_metrics/test_recog_metric.py
imports: import unittest
  from mmengine.structures import LabelData
  from mmocr.evaluation import CharMetric, OneMinusNEDMetric, WordMetric
  from mmocr.structures import TextRecogDataSample
label_desc: Use image node_id 1 for calling the TestCharMetric obj's underlying member method code with example usage: obj.setUp() without return types